Simple Firm Session Manager by kbtanvir.dev

Simple Firm Session Manager lets you save and restore all tabs in your current window. When you restore a session, tabs are loaded in a sleeping state — they don't consume memory until you click on them.

Features

Save all open tabs as a named session
Restore sessions with sleeping (discarded) tabs to save memory
Preserves pinned tabs and tab groups in the correct order
Rename or delete sessions from the popup
Optional: export sessions as JSON files to your Downloads folder for backup
Import sessions back by selecting the exports folder from the Settings page
All data is stored locally in your browser. No accounts, no telemetry, no network requests of any kind.